DESCRIPTION: The replacement of damaged or missing cells is an emerging treatment strategy for a number of neurological disorders. Methods for the collection and storage of fetal neural tissue must provide sufficient quantities of viable cells, thus offering time for scheduling, treatments, cell identification, biological safety, or tissue matching. The principal investigator and his colleagues have developed a cryopreservation method for storage of dopaminergic neuroblasts for transplantation. Although this method can produce impressive grafts, comparable to those derived from fresh tissue, the outcome is variable and with some costs in viability. Parameters that lead to optimal graft survival have not been determined. The applicant proposes, therefore, to test a series of hypotheses which might improve fetal human CNS tissue collection, cryopreservation, and storage procedures, and long-term survival after transplantation. The hypotheses and experiments will test the neurotoxicity of tissue incubation procedures and solutions, cryoprotectants, slow freezing, vitrification, and protective effects of drugs and growth factors. Viability and function will be tested first using simple and efficient outcome measures to maximize the number of variables that can be studied. Using organotypic slice culture preparations, these investigators will identify viability, apoptosis, cell types, biochemical, and electrophysiological function as outcome measures to test hypotheses addressing different biological and technical variables. To ensure that findings from animal models are relevant to clinical applications, they also will study both rodent and human fetal neural tissue using the same outcome measures. The results of these studies will be useful for developing potentially therapeutic neural tissue implants for neurological disorders such as Huntington's, Alzheimer's, Parkinson's disease, and spinal cord injury. Since viable human embryonic neural tissue of defined age and characteristics is difficult to collect, a method for long-term cell banking, typing, and storage is essential for basic research and clinical applications for neural transplantation. But cryopreser-vation potentially has even broader applicability for studies of neuronal development, regulation, and cellular characteristics that may be relevant to such human conditions as Down's syndrome, Alzheimer's, Huntington's, schizophrenia, and Parkinson's disease.